Resolve a Constraint Conflict

Resolve a Constraint Conflict

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With the lengths of two sides and the included angle already constrained, the triangle is already fully defined; any new constraint you add will conflict with the existing ones. While this may be obvious, you may later encounter conflics that are less obvious. This task takes you through the steps necessary to resolve such conflicts.

  1. Select the line AC and add a length constraint. Youll see this dialog:

Tutorial 1 (Constraint Conflict) 

  1. The dialog offers you three choices:
  • Cancel out of the operation, leaving the drawing as it was.
  • Leave the other constraints in place and calculate the requested distance from them. This replaces the requested length constraint with a length output expression instead.
  • Relax one of the existing constraints so you can add the new one. You can then choose which to relax.
  1. Click the second radio button, Calculate the distance from the other constraints, and dismiss the dialog. Youll see the expression appear with the arrow (=>) that indicates its an output. It may also be given a name. This will be the case if the Show Name (in the Display Properties dialog box) is set to True.

Tutorial 1 (Display Properties) 

  1. Edit > Undo
  2. Try to add the new constraint again. This time, click the third radio button, Relax other constraints so the distance is independent. As soon as you click it, the conflicting constraints highlight in red and the new one in yellow:

Tutorial 1 (Constraint Conflict)_2 

  1. Click on the angle at B. Its highlight changes to indicate its selected; the conflicting constraint highlights vanish, and the new one now highlights in green.

Tutorial 1 (Constraint Conflict)_3 

  1. Click OK. Now the figure includes the length constraint c, while the perpendicular angle constraint at B is gone.

 

  1. Edit > Undo again. Were going to need that perpendicular angle later. Leave the drawing as it was, without length constraint c.